System and method for laser generated corneal and crystalline lens incisions using a variable F/# optical system with aspheric contact interface to the cornea or rotating and adaptive optics

ABSTRACT

A laser system including a laser source that generates a laser beam and an optical switch that receives the laser beam and selectively sends the laser beam to either a fast path or a slow path, wherein in the fast path the laser beam has a first F/# and in the slow path the laser beam has a second F/# that is higher in value that of the first F/#. The laser system further including an afocal optical system that is in the slow path and receives the laser beam from the optical switch and an x-y scanner that receives either a first laser beam from the slow path or a second laser beam from the fast path. The laser system including a scan lens system that receives a scanning laser beam from the x-y scanner and performs a z-scan for the scanning laser beam only in the case wherein the scanning laser beam is generated from the laser beam in the fast path. The laser system further including an aspheric patient interface device that receives a laser beam from the scan lens system.

This application is a divisional of U.S. application Ser. No. 13/435,103filed Mar. 20, 2012, which application claims the benefit of priorityunder 35 U.S.C. § 119(e)(1) of 1) U.S. Provisional Application Ser. No.61/470,734, filed Apr. 1, 2011 and 2) U.S. Provisional Application Ser.No. 61/550,101, filed Oct. 21, 2011, the entire contents of each ofwhich is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a system and method for laser generatedcorneal and crystalline lens incisions.

BACKGROUND

Recently, femtosecond laser systems are emerging as an alternative tomanual incisions in the cornea and crystalline lens for differentophthalmic surgeries. Examples of such laser systems are the IntralaseFS Laser and IFS Advanced Femtosecond Laser manufactured and sold byAbbott Medical Optics of Abbott Park, Ill. and the LenSx FemtosecondLaser manufactured and sold by LenSx Lasers of Aliso Viejo, Calif. Suchlasers make incisions by focusing ultrashort laser pulses to a very finefocus, causing a plasma mediated photodisruption of the tissue at thepoints of focus. The incision is generated by placing a contiguousseries of such pulses in the pattern of the desired incision. Thecombined effect of the pattern of pulses is cleaving the tissue at thetargeted plane. Arbitrarily complex incision patterns can be generatedwith such lasers. Furthermore, femtosecond lasers are believed to makemore accurate and consistent incisions than the incisions formedmanually.

The image space F/# of a beam delivery optical system, such as thefemtosecond laser systems described previously, is defined as the focallength relative to the aperture of the system (F/#=f/D, wherein f is thefocal length of the beam delivery optical system and D is the entrancepupil diameter). The diameter of a laser spot formed by a beam deliverysystem is directly proportional to the F/# of the system. Therefore, ingeneral, a low F/# beam delivery optical system is desirable in order toobtain a small focal point in the eye, and therefore maximize thespatial peak irradiance at the focal plane. This allows for a reductionof the laser energy necessary to produce photodisruption, resulting in asmaller shock wave and with smaller zone of collateral damage and lessheat transferred to the adjacent tissue. Also, due to the small volumeof tissue where photodisruption occurs, a low F/# system allows for highprecision cuts with complex patterns.

However, low F/# systems are very susceptible to optical aberrations asthe laser beam passes through the optics and the transparent tissue ofthe eye. Such aberrations alter the spatial irradiance distribution atthe focal point, reducing the peak irradiance. Furthermore, in a low F/#system, aberrations vary with the position of the focal point within theeye. For example; in general, the deeper into the tissue the beam isfocused, and the further off the axis of the focusing optics the beam isfocused, the greater the aberrations. The aberrations are also generallyincreased significantly when the beam must pass from across curvedinterfaces between two transparent materials of different refractiveindices. Since creating incisions in the cornea and lens requiresfocusing relatively deep into the tissue, focusing considerably off axisand crossing curved interfaces between transparent materials, it is verychallenging to design an optical system capable of focusing a beam overa large three-dimensional working space in the eye using a low F/# beamdelivery system while maintaining a relatively unaberrated focal pointthroughout the entire three-dimensional space.

Currently, there are ophthalmic surgery systems specializing in cuttinginto the cornea using low F/# beam delivery optical systems, such as theIntralase FS system manufactured and sold by Abbott Medical Optics ofAbbott Park, Ill., the VisuMax Femtosecond system manufactured and soldby Carl Zeiss Meditech of Dublin, Calif. and the Technolas FemtosecondWorkstation manufactured and sold by Technolas Perfect Vision ofMünchen, Germany. However, these systems only cover a limitedthree-dimensional working space. In particular, although a beam focusmust be formed off-axis, the depth of the incisions is limited to nomore than the depth of the cornea, about 600 μm. Furthermore, in some ofthese systems it is required to flatten the cornea in order to eliminateaberrations such as coma and astigmatism that result from the laser beampassing through the curved cornea. No current system has fully addressedthe challenging problem of generating a sharp, minimally aberrated beamfocus to generate incisions over the full diameter of the cornea andfull depth of the cornea and crystalline lens. In other words, nocurrent systems, such as the previously mentioned low F/# beam deliveryoptical systems, cover any specific method to reduce aberrations whilecovering a large three-dimensional working space in the eye using a lowF/# optical system.

BRIEF SUMMARY

One aspect of the present invention regards a laser system including alaser source that generates a laser beam and an optical switch thatreceives the laser beam and selectively sends the laser beam to either afast path or a slow path, wherein in the fast path the laser beam has afirst F/# and in the slow path the laser beam has a second F/# that ishigher in value that of the first F/#. The laser system furtherincluding an afocal optical system that is in the slow path and receivesthe laser beam from the optical switch and an x-y scanner that receiveseither a first laser beam from the slow path or a second laser beam fromthe fast path. The laser system including a scan lens system thatreceives a scanning laser beam from the x-y scanner and performs az-scan for the scanning laser beam only in the case wherein the scanninglaser beam is generated from the laser beam in the fast path. The lasersystem further including an aspheric patient interface device thatreceives a laser beam from the scan lens system.

A second aspect of the present invention regards a method of surgicallyrepairing an eye that includes generating a laser beam and selectivelysending the laser beam to either a fast path or a slow path, wherein inthe fast path said laser beam has a first F/# and in the slow path thelaser beam has a second F/# that is higher in value than that of thefirst F/#. The method including having an afocal optical system in theslow path and performing an x-y scan of either a first laser beam fromthe slow path or a second laser beam from the fast path. The methodfurther including having a scan lens system receive a scanning laserbeam based on said x-y scanning and perform a z-scan for the scanninglaser beam only in the case wherein the scanning laser beam is generatedfrom the laser beam in the fast path. The method further includinghaving an aspheric patient interface device receive a laser beam fromthe scan lens system, wherein the aspheric patient interface device isin contact with a cornea of an eye and directs the laser beam from thescan lens system to either 1) the cornea only in the case wherein thescanning laser beam is generated from the laser beam in the fast path or2) a crystalline lens of the eye only in the case wherein the scanninglaser beam is generated from the laser beam in the slow path.

A third aspect of the present invention regards a method of reducingaberrations during surgical repair of an eye, the method includingpositioning an aspherical patient interface device so as to contact acornea of an eye, wherein the cornea is not flattened during thepositioning and the cornea conforms to a shape of a bottom surface ofthe aspherical patient interface device. The method including directinga laser beam through the aspherical patient interface device to a volumeof the eye, wherein the laser beam does not suffer from aberrations whenarriving at the volume of the eye.

A fourth aspect of the present invention regards a scan lens system thatincludes a first lens, a second lens, a third lens and a fourth lens,wherein the first lens, second lens, third lens and the fourth lens arearranged in series with one another. In addition, the second lens andthe third lens are each positioned between the first lens and the fourthlens and wherein the second lens and the third lens are stationary withrespect to each other and the first and fourth lenses can move in unisonrelative to the second lens and the third lens.

A fifth aspect of the present invention regards an afocal system thatincludes a first negative lens, a second negative lens, a first positivelens and a second positive lens, wherein the first positive lens, thesecond positive lens, the first negative lens and the second negativelens are in series with one another. In addition, the first positivelens and the second positive lens are fixed in position while the firstnegative lens and the second negative lens move in unison to one anotherrelative to the first positive lens and the second positive lens.

A sixth aspect of the present invention regards a laser system thatincludes a laser source that generates a laser beam along a fast path,wherein the laser beam in the fast path has a F/# having a value rangingfrom F/1.5 to F/4. The laser system further including an asphericpatient interface device that receives the laser beam from the lasersource, wherein the aspheric patient interface device is in contact witha cornea of an eye and directs the laser beam to the cornea.

A seventh aspect of the present invention regards a laser system thatincludes a laser source that generates a laser beam along a path and anafocal optical system that is in the path and receives the laser beamfrom the laser source and an F/# varying element that is in the path andchanges the laser beam so that it has either a first F/# value or asecond F/# value. The laser system includes an x-y scanner that receivesthe changed laser beam having either the first F/# value or the secondF/# value and a scan lens system that receives a scanning laser beamfrom the x-y scanner and performs a z-scan for the scanning laser beamonly in the case wherein the changed laser beam has the first F/# value.The laser system further including an aspheric patient interface devicethat receives a laser beam from the scan lens system.

An eighth aspect of the present invention regards an ophthalmic lasersystem including a laser source that generates a laser beam and anoptical switch that receives the laser beam and selectively sends thelaser beam to either a fast path or a slow path, wherein in the fastpath the laser beam has a first F/# and in the slow path the laser beamhas a second F/# that is higher in value than the first F/#. Theophthalmic laser system including an adaptive optic device that is inthe fast path and an x-y-z translation device that receives either afirst laser beam from the slow path or a second laser beam from the fastpath. The ophthalmic laser system further including a rotating opticalsystem that receives a laser beam from the x-y-z translation device andperforms a partial or full circular scan of the received laser beamabout an axis of rotation of the rotating optical system, wherein therotating optical system is able to translate so as to vary a radius ofthe partial or full circular scan and the partial or full circular scanis positioned in an eye of a patient. In addition, the adaptive opticcorrects the laser beam received form the fast path so that aberrationsat the partial or full circular scan are significantly reduced.

A ninth aspect of the present invention regards an ophthalmic lasersystem that includes a laser source that generates a laser beam and anoptical switch that receives the laser beam and selectively transformsthe laser beam to either a fast path laser beam or a slow path laserbeam, wherein the fast path laser beam has a first F/# and the slow pathlaser beam has a second F/# that is higher in value than first F/#. Anadaptive optic device receives either the fast path laser beam or theslow path laser beam from the optical switch. An x-y-z translationdevice that receives either the fast path laser beam or the slow pathlaser beam from the adaptive optic. The ophthalmic laser system furtherincluding a rotating optical system that receives a laser beam from thex-y-z translation device and performs a partial or full circular scan ofthe received laser beam about an axis of rotation of the rotatingoptical system, wherein the rotating optical system is able to translateso as to vary a radius of the partial or full circular scan and thepartial or full circular scan is positioned in an eye of a patient. Inaddition, the adaptive optic corrects the fast laser beam so thataberrations along the partial or full circular scan are significantlyreduced.

A tenth aspect of the present invention regards a method of surgicallyrepairing an eye that includes generating a laser beam and selectivelymanipulating the laser beam so that the laser beam is present in eithera fast path or a slow path, wherein in the fast path the laser beam hasa first F/# and in the slow path said laser beam has a second F/# thatis higher in value than the first F/#. The method includes having anadaptive optic device that is in the fast path to receive theselectively sent laser beam in the fast path and having an x-y-ztranslation device that receives either the fast path laser beam or theslow path laser beam from the adaptive optic. The method furtherincludes receiving a laser beam from the x-y-z translation device andperforming a partial or full circular scan of the received laser beamand varying a radius of the partial or full circular scan, wherein thepartial or full circular scan is positioned in an eye of a patient. Inaddition, the adaptive optic corrects the laser beam received from thefast path so that aberrations along the partial or full circular scanare significantly reduced.

An eleventh aspect of the present invention regards a rotating opticalsystem that includes a housing that rotates about an axis of rotation,wherein the housing has a window to receive a laser beam. The rotatingoptical system includes a translating stage that is present within thehousing and translates relative to the housing, the translating stagehaving a lens. The rotating optical system further including an opticalsystem for directing the laser beam from the window to the lens, whereinthe lens directs the laser beam to a focal point exterior of thehousing.

A twelfth aspect of the present invention regards an adaptive optic thatincludes a beam splitting device that has an input side for receivinglight and an output side for transmitting light. The adaptive opticfurther including a deformable mirror that receives the received lightfrom the input side and directs the received light to the output side.

One or more aspects of the present invention allow for a reduction inthe complexity of optics in an ophthalmic beam delivery optical system.Another advantage of this present invention is that the adaptive opticdevice allows for significant flexibility in correcting variousaberrations that may occur in the laser beam.

One or more aspects of the present invention allow for a reduction inthe complexity of optics and the number of moving elements in a beamdelivery optical system.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying drawings, which are incorporated herein and constitutepart of this specification, and, together with the general descriptiongiven above and the detailed description given below, serve to explainfeatures of the present invention. In the drawings:

FIG. 1 schematically shows a Gaussian beam that shows various parametersof a beam;

FIG. 2 schematically compares beam waist and Rayleigh range values forlow F/# and high F/# beams;

FIG. 3 schematically shows a cross-section of an eye;

FIG. 4 schematically shows a first embodiment of a beam delivery opticalsystem in accordance with the present invention;

FIG. 5 schematically shows and embodiment of an aspheric lens to be usedwith the beam delivery optical system of FIG. 4 in accordance with thepresent invention;

FIG. 6 schematically shows an embodiment of a scan lens system to beused with the beam delivery optical system of FIG. 4 in accordance withthe present invention;

FIG. 7A schematically shows an embodiment of a z-scan afocal system tobe used with the beam delivery optical system of FIG. 4 in accordancewith the present invention;

FIG. 7B shows an enlarged view of the afocal system of FIG. 7A;

FIG. 8 schematically shows a second embodiment of a beam deliveryoptical system in accordance with the present invention;

FIG. 9 schematically shows a third embodiment of a beam delivery opticalsystem in accordance with the present invention;

FIG. 10 schematically shows a fourth embodiment of a beam deliveryoptical system in accordance with the present invention;

FIG. 11 schematically shows a fifth embodiment of a beam deliveryoptical system in accordance with the present invention;

FIG. 12A schematically shows a first embodiment of an adaptive opticaldevice to be used with the beam delivery optical system of FIG. 11 inaccordance with the present invention;

FIG. 12B schematically shows an alternate embodiment of an adaptiveoptical device to be used with the beam delivery optical system of FIG.11 in accordance with the present invention;

FIG. 13 schematically shows an embodiment of an x-y-z translation deviceto be used with the beam delivery system of FIG. 11;

FIG. 14 schematically shows an embodiment of a rotating optical systemto be used with the beam delivery system of FIG. 11;

FIG. 15 shows a top view of typical circular incisions/cuts patterns inthe case where the beam is formed through the fast path;

FIG. 16A schematically represents an example where an unaberratedwavefront is directed to optics which results in aberrated wavefrontsafter passing through a cover window, a cornea and other portions of aneye before arriving at a focal point;

FIG. 16B schematically represents the case where the unaberratedwavefront of FIG. 16A is corrected by either one of the adaptive opticaldevices of FIGS. 12A-B so that aberrations introduced in the laser beamby refractions at various transparent interfaces are corrected by theadaptive optic device;

FIG. 17A schematically shows crystalline lens fragmentation cuts thatinclude transversal arc-shaped cuts and circular cuts, which are donewith the slow laser beam (large F/#);

FIG. 17B shows a typical example of a circular path described by thelaser focus when cutting transversal arc-shaped cuts during thefragmentation of a crystalline lens;

FIG. 18 schematically shows a sixth embodiment of a beam deliveryoptical system in accordance with the present invention;

FIG. 19 schematically shows a seventh embodiment of a beam deliveryoptical system in accordance with the present invention; and

FIG. 20 schematically shows an eighth embodiment of a beam deliveryoptical system in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Note that in order to understand some of the properties of the presentinvention, FIG. 1 is presented which schematically shows a beam, such asa Gaussian beam 100. The beam waist W₀ and Rayleigh range Z_(R) are twokey parameters that determine how localized the photodisruption andadditional thermal effects will be around the focal point of the beam.The beam waist is directly proportional to the beam F/#, so the peakspatial irradiance at the waist is inversely proportional to the squareof the F/#. The Rayleigh range of a Gaussian beam is defined as thedistance along the laser beam (Z-axis) from the beam waist to the pointwhere the beam expands by sqrt(2), and is directly proportional to thesquare of the beam waist. Therefore, the Rayleigh range is inverselyproportional to the square of the F/#. Note that at one Rayleigh rangeaway from the waist, the peak irradiance will drop in half compared tothe peak irradiance at the waist. With the above said, the Rayleighrange and waist for a high F/# beam will be larger than the Rayleighrange for a low F/# beam as shown in FIG. 2.

As shown by the shaded areas of FIG. 3, there are two areas of interestregarding the formation of incisions or cuts in an eye 200—the cornea202 and the crystalline lens 204. In the case of cuts formed in thethree-dimensional working space A (see hashed line area of cornea 202 ofFIG. 3) in the cornea 202, it is desirable to reduce the Rayleigh rangeand waist of the laser beam, as high precision and the ability to cutcomplex patterns within a very small volume are critical factors incutting the cornea (Clear Corneal Incisions—CCIs, Limbal RelaxationIncisions—LRIs, flaps). A shorter Rayleigh range reduces the depth ofthe cut formed by a single laser pulse on the Z-axis, increasing theaccuracy of placing LRI cuts in terms of length and location on Z. Theaccuracy of LRIs in Z is important so that LRIs could be placedrelatively close to the endothelium without the risk of completelycutting through the cornea into the anterior chamber. In the case ofCCIs, a shorter Rayleigh range allows cutting more complex and precisepatterns as viewed in the cross-section formed by a plane containing theZ-axis. Such patterns are beneficial as they help sealing the CCI afterthe cataract surgery. In addition, with a shorter Rayleigh range thebeam irradiance decreases faster with Z from the beam waist, whichallows cutting into the corneal stroma without damaging the epitheliumor endothelium due to thermal effects. Based on the above advantages ofusing a beam of a shorter Rayleigh range, low F/# beams are preferredfor forming cuts in the cornea 202.

In the case of cuts formed in the three-dimensional working spaces B(see hashed line areas in the vicinity of the anterior capsule 203 ofthe crystalline lens 204 of FIG. 3) in the vicinity of the anteriorcapsule 203 of the crystalline lens 204 during a capsulotomy, it isdesirable to reduce the Rayleigh range and waist of the laser beam inorder to minimize the potential collateral damage to the area of theanterior capsule that is in close proximity to the capsulotomy cut. In atypical capsulotomy performed with a laser beam, laser pulses aredirected in a cylindrical pattern (of diameter equal to the desiredcapsulotomy diameter), starting in the crystalline lens 204, posteriorto the anterior capsule 203, and moving upwards through the anteriorcapsule 203, towards the anterior chamber 206. A shorter Rayleigh rangeand a smaller laser beam waist ensure that when the laser beam waist isfocused posterior or anterior to the anterior capsule 203, less energydensity falls onto the area of the anterior capsule that is in closeproximity to the capsulotomy cut, which preserves the elasticity of thecapsule around the cut, therefore improving the strength of the capsulearound the cut. A smaller laser beam waist also allows for less laserenergy to be used for capsulotomy, and ensures a cleaner cut, furtherimproving the strength of the anterior capsule 203 around the cut. Astrong capsule tissue around the capsulotomy reduces the possibility ofunwanted tears in the anterior capsule 203 during the capsulorhexis,improving the precision of placing the intra-ocular lens during acataract surgery, which is one of the critical factors in the outcome ofthe surgery. Based on the above advantages of using a beam of a shorterRayleigh range and smaller waist, low F/# beams are preferred forforming cuts in the anterior capsule 203.

When cutting the three-dimensional working space C (see hashed line areaof crystalline lens 204 of FIG. 3) of crystalline lens 204, the laserbeam passes through more tissue with variable or unknown properties thanin the case of the corneal cuts. This results in less predictablerefractions of the beam and therefore less predictable aberrations,which could not be accounted for in the optical design, and thereforewould remain uncorrected. Therefore, in the case of the crystalline lenscuts or incisions (fragmentation and capsulotomy) performed in generalor, in particular, performed in space C it is desirable to use a highF/# beam, because such a beam is less sensitive to the aberrationsintroduced by the patient-to-patient variations in the eye geometry(anterior chamber depth, thicknesses and radii of curvature of thecornea and crystalline lens) and the refractive index of the crystallinelens 204.

Also, due to the less complex nature of the typical cutting patterns forthe fragmentation and capsulotomy, the precision required is relativelylower compared to the precision required for the corneal cuts. Cornealcuts need to have the depth (on Z-axis) controlled to a few tens ofmicrons or about 5% of the thickness of the cornea 202; crystalline lenscuts need to have a z control in the range of a couple of hundredmicrons or about 5% of the thickness of the crystalline lens 204.

With the above discussion regarding the desire to form cuts in thecornea 202 with a low F/# beam and form cuts in the crystalline lens 204with a high F/# beam, an embodiment of a beam delivery optical system300 that can form cuts with both types of beams is illustrated in FIG.4. In particular, a laser beam 302 is generated by a laser source 304and directed via mirrors 306, 308 to an optical switch 310. The opticalswitch 310 includes a λ/2 wave plate 312 and a polarization beamsplitter cube (PBSC) 314. Rotating a λ/2 wave plate by a certain anglerotates the polarization of an incident linearly polarized beam bydouble the said angle, so the λ/2 wave plate 312 in the optical switch310 acts as a polarization rotator. A PBSC reflects all light with thepolarization parallel to the plane of its reflective surface andtransmits all light with the polarization 90 degrees rotated withrespect to the reflected polarization. With the above said, as the laserbeam 302 is linearly polarized, rotating the λ/2 wave plate 312 in afirst position allows the laser beam 302 to pass entirely through thePBSC 314 to travel along a fast path 319 and not a slow path 316 of thesystem 300. Rotating the λ/2 wave plate 312 by 45 degrees with respectto the first position allows the laser beam 302 to be entirely reflectedby the PBSC 314 and directed to a mirror 318 so that the laser beam 302travels along the slow path 316 and not the fast path 319. Thus, theoptical switch 310 switches the laser beam 302 between the fast path 319and the slow path 316, wherein only one path at a time is used duringcutting. While the λ/2 wave plate 312 rotates by 45 degrees to switchbetween the slow path 316 and the fast path 319, the laser will be shutoff. So, it will be a short delay during which the laser beam will be“off” allowing to completely switch between the two paths

In the fast path 319, the laser beam 302 is expanded by a beam expander320 with a magnification equal to the ratio between the F/# of the beamdirected along the slow path 316 and the F/# of the laser beam directedalong the fast path 319. The expansion of the beam is equivalent toexpanding the entrance pupil diameter D and so the F/# is reduced. Thus,beam expander 320 acts as an F/# varying element. Note that theparticular magnification for beam expander 320 is chosen in view of thefact that the beam in the slow path is not expanded. The expanded laserbeam 322 is then directed through a second PBSC 324 and passed on to anx-y scanner 326. The x-y scanner 326 is used to direct the light througha scan lens to particular areas of the eye in a well known manner. Thelight from the x-y scanner is focused through a scan lens system 328,which focuses the scanning laser beam through the aspheric patientinterface device 330 into the eye. After passing through the scan lenssystem 328, the light is then directed to an aspheric patient interfacedevice 330 that is in contact with the cornea 202 of the eye 200 that isbeing surgically repaired. The laser beam is then directed to the cornea202 wherein incisions or cuts are made thereto pursuant to apredetermined pattern. The details regarding the beam expander 320, thescan lens system 328 and the aspheric patient interface device 330 willbe explained later in the present application.

When the optical switch 310 directs light along the slow path 316, thelaser beam goes through a z-scanning afocal optical system 332 withvariable output beam divergence. The magnification of the afocal system332 is 1 when the output beam divergence is at its minimum value. Theuse of such an afocal optical system 332 in the slow path 316 is neededto achieve scanning in a vertical axis of the eye 200 (defined here asZ-axis) by varying the divergence of the laser beam as will be discussedlater. As shown in FIG. 4, the fast path 319 and the slow path 316 (viamirror 333) are recombined by the second polarization beam splitter cube(PBSC) 324 and both sent into the horizontal x-y scanner 326.

Note that the operation of PBSCs 314 and 324 is such that all lightreflected by PBSC 314 into the slow path will be reflected by PBSC 324back onto the optical axis of the x-y scanner/scan lens due to thepolarization being parallel to the reflecting surface of both PSCs.Likewise, all light transmitted by PBSC 314 will be transmitted by PBSC324. The advantage of using PBSCs is that the power loss is minimizedthrough the system since they transmit or reflect all light.

In the case of the slow path 316 and the laser beam leaving PBSC 324 andsent to scanner 326, the laser beam from the scanner 326 is then sent toscan lens system 328. When the beam is delivered through the slow path316, all elements within the scan lens system 328 are fixed andconfigured to generate the deepest cut. The low F/# scanning laser beam334 from scan lens system 328 is then directed through the asphericpatient interface device 330 to the crystalline lens 204 whereinincisions or cuts are made thereto pursuant to a predetermined pattern.The details regarding the z-scanning afocal optical system 332 will beexplained later in the present application.

An example of the aspheric interface device 330 used in the beamdelivery optical system 300 of FIG. 4 is shown in FIG. 5. In particular,a meniscus aspheric precision glass molded lens 400 can be used fordevice 330 and is placed in contact with the anterior surface 206 of thecornea 202. Note that the device 330 should be positioned initially tobarely touch the cornea at the center wherein x-y adjustment is made ifnecessary. Once centered, suction is applied to lift up the limbus untilit contacts the lens 400. The lens 400 is preferably manufactured by aprecision glass molding process, which is a very well suited fabricationmethod for high-volume production when precision is an important factor.The lens 400 can be molded directly into a metal holder, or a plasticholder can be injection-molded around the lens after the lens is molded.Such manufacturing processes are known to be performed by severalmanufacturers, such as LightPath of Orlando, Fla. and RPO—RochesterPrecision Optics of Rochester, N.Y. The lens 400 can have the followingproperties: 1) 2 mm center thickness, 2) meniscus shaped, 3) BK-7 glassand 4) 18 mm diameter. Other moldable glasses, includingradiation-hardened glasses, such as Ce-doped glasses, can be used forlens 400. Note that the dimensions and type of glass can be variedwithout departing from the spirit of the invention.

The top (convex) surface 402 of the lens 400 is aspheric and describedby an even-aspheric equation. The bottom surface 404 of the lens 400 isalso aspheric and described by a conic equation. This lens 400 allowsfor precise positioning of the cornea 202 with respect to the rest ofthe beam delivery optics (centration, tilt, depth), and will alsoprovide a fixed and known shape of the anterior surface of the cornea202 during the formation of the surgical cuts. The range of anteriorcorneal radii is about 7.00-8.65 mm with an approximate conic constantK=−0.2. The cornea 202 is not flattened, but rather conformed to asurface with a slightly larger radius and a similar conic (for example:R=9 mm, K=−0.2). The conic shape of the portion of the bottom surface404 in contact with the cornea 202 emulates the natural slight increasein radius of the cornea 202 towards the limbus, and, thus, decreases thepossibility of folds in the cornea 202 or air being trapped between theglass lens 400 and cornea 202. Another very important advantage of thisinterface is the ability to use the anterior aspheric surface 402 of themolded lens 400 (air-glass interface) as a “field lens.” Since thisaspheric surface 402 is so close to the working space in the cornea 202,it can be used very effectively in combination with the scan lens system328 to reduce aberrations like astigmatism and coma when cutting thecornea 202 with a low F/# laser beam 336 at different radial positionsand different depths. In addition, a low F/# laser beam can be generatedand sent directly to lens 400 that is in contact with the cornea of theeye. The lens 400 by itself reduces the effect of aberrations whencutting the cornea 202 with the low F/# laser beam.

Regarding the scan lens system 328, an embodiment is shown in FIG. 6. Inparticular, the scan lens system 328 includes four lenses 502, 504, 506and 508 contained in a lens mechanical housing (not shown). The middlelenses 504 and 506 are stationary with respect to each other and thehousing, and are separated from one another by approximately 0.5 mm. Theouter lenses 502 and 508 are a distance of approximately 46 mm from eachother and are able to translate in unison by a total amount ofapproximately 2.5 mm. The distance between lens 502 and lens 504 variesbetween 9 mm and 6.5 mm as lenses 502 and 508 are moving together byapproximately 2.5 mm to achieve the z-scanning for the low F/# laserbeam. As shown in FIG. 6, the edge of the rear surface of lens 508 isapproximately 38 mm from the front surface 402 of lens 400. In addition,the edge of the front surface of the lens 502 is approximately 30 mmaway from the entrance pupil 510 of the scan lens system 328, whichallows placing the center of rotation of an X-Y scanner 326 with a 30 mmaperture at the entrance pupil of the scan lens system 328.

Note that lens 502 is a cemented doublet with negative power (focallength of approximately −250 mm) formed by a negative meniscus lens witha center thickness of approximately 5 mm cemented to a positive meniscuslens with a center thickness of approximately 12 mm. Lens 504 is acemented doublet with positive power (focal length of approximately 270mm) formed by a negative meniscus lens with a center thickness ofapproximately 6 mm cemented to a positive bi-convex lens with a centerthickness of approximately 18 mm. Lens 506 is a meniscus shaped singletwith positive power (focal length of approximately 150 mm) with a centerthickness of approximately 12 mm. Lens 508 is a meniscus shaped singletwith positive power (focal length of approximately 100 mm) with a centerthickness of approximately 11 mm. All diameters of lenses 502, 504, 506,and 508 are smaller than approximately 72 mm.

In operation, scan lens system 328 has an effective focal length ofapproximately 45 mm and an entrance pupil 510 of approximately 30 mm.When receiving the laser beam from the fast path, the scan lens system328 is capable of delivering an F/1.5 laser beam into the cornea 202while covering the full three-dimensional working space A in the cornea202 as defined in FIG. 3 (13 mm maximum cut diameter), and maintaining aStrehl-Ratio larger than approximately 0.8 (the Strehl-Ratio is definedas the spatial peak irradiance of the aberrated focal spot relative tothe peak irradiance of an aberration-free spot). During surgery, the x-yscanner 326, the scan lens system 328, and patient interface device 330are fixed with respect to one another. The vertical scanning (on theZ-axis) for the laser beam from the fast path is performed by the scanlens system 328 by moving axially along the Z axis the front and backlenses 502 and 508 together (as a common body). While the lenses 502 and508 move, the lenses 504 and 506 are fixed with respect to the lensmechanical mount. Note that the lens scan system 328 can include anactuator (motor) onto which lenses 502 and 508 would be mountedtogether. The motor would be mounted on the scan lens system 328, whichis fixed with respect to the eye 200 and with respect to the x-y scanner326. In the case of a laser beam received from the fast path, thecombination of this axial movement of lenses 502 and 508 in the scanlens system 328, x-y scanning angle, and the aspheric lens 400 used asthe patient interface device 330 allows placing the focused beam waistat different points in the required three-dimensional working space A inthe cornea. In addition, it is very important to note that this scanningcombined with the aspheric patient interface 330 automatically correctsthe aberrations that vary with the position of the focal point withinthe cornea 202.

On the slow path, the system delivers an F/4 beam into the crystallinelens working space B as defined in FIG. 3. In the slow pathconfiguration, the moving elements within the scan lens system 328remain fixed in the position corresponding to the deepest corneal cut,while the scanning on the Z-axis is done by varying the divergence ofthe beam generated by the afocal system 332. The optical arrangement forthe afocal system 332 that performs the Z-scanning for a beam in theslow path 316 is shown in FIGS. 7A-B. As shown in FIG. 7B, system, theafocal system 332 includes negative lenses 600 and 604 and positivelenses 602 and 606. The lenses 602 and 606 are fixed to a mechanicalhousing so as to be a distance of 21 mm from one another.

Note that lens 600 is a negative meniscus singlet with a focal length ofapproximately −30 mm and a center thickness of approximately 2 mm. Lens602 is a positive bi-convex singlet with a focal length of approximately20 mm and a center thickness of approximately 3 mm. Lens 604 is anegative bi-concave singlet with a focal length of approximately −10 mmand a center thickness of approximately 1.5 mm. Lens 606 is a positivemeniscus singlet with a focal length of approximately 35 mm and a centerthickness of approximately 3 mm. The spacing between lens 600 and lens602 is approximately 9 mm. The lenses 600 and 604 move in unison witheach other with respect to the lenses 602 and 606 by a totaldisplacement of approximately 6 mm. The particular arrangement andrelative motion of lenses 600, 602, 604 and 606 form an optical zoomconfiguration that allows placing the z-scanning afocal system 332further away from the scan lens system 328 (when compared with knownconfigurations for z-scanning afocal systems that include thecommercially available two-element Galilean telescope embodiment thatincludes a negative element followed by a positive element, where thenegative element is moved with respect to the positive element) whilestill maintaining a constant F/# at the image plane over the full Z scanrange. Placing the afocal system 332 further away from the scan lenssystem 328 is beneficial due to various mechanical constraints, like thesize of the second PBSC 324 and the size of the x-y scanner 326. Theoptical zooming helps with the increased spacing from the scan lenssystem 328 in that while divergence increases, the output beam from theafocal system 332 decreases to keep the beam diameter at the input ofthe scan lens system 328 somewhat constant. That way, the F/# of thebeam coming out of the scan lens stays constant while scanning on Z.

Note that other embodiments for a dual beam delivery optical system arepossible. An example of such an optical system is the beam deliveryoptical system 700 shown in FIG. 8. The structure of beam deliveryoptical system 700 is similar to beam delivery optical system 300 ofFIG. 4. In particular, a laser beam 302 is generated by a laser source304 and directed via mirrors 306, 308 to an optical switch 310. Incontrast to the λ/2 wave plate 312 and polarization beam splitter cube(PBSC) 314 of FIG. 4, the system 700 uses a turning mirror 702 that canrotate to a first position so that the laser beam 302 is directed tomirror 318 and the slow path so that it can be processed by afocalsystem 332 in a manner as described with respect to the embodiment ofFIG. 4. Rotating turning mirror 702 causes the laser beam 302 to reflectoff of mirror 704 and directed to the fast path to be processed by thebeam expander 320 in a manner as described with respect to theembodiment of FIG. 4.

As shown in FIG. 8, the fast path laser beam is deflected by a mirror708 to a second turning mirror 706 which is positioned at a firstposition to reflect the fast path laser beam to the x-y scanner 326.Similarly, the slow path laser beam is deflected by a mirror 333 to theturning mirror 706 which is positioned at a second position to reflectthe slow path laser beam to the x-y scanner 326. The slow path and fastpath laser beams are processed and scanned by the afocal system 332, x-yscanner 326, scan lens 328 and aspheric patient interface device 330 ina manner similar to that described with respect to the embodiment ofFIG. 4.

Note that in operation, the rotation of mirrors 702 and 706 aresynchronized so that the laser beam 302 passes through either only thefast path 319 or the slow path 316. In addition, the laser beam 302 isstopped or the laser 304 is shut off during rotation of the mirrors 702and 706.

Other possibilities for the optical switch 310 of FIG. 8 are possible.For example, the mirrors 702 and 706 can be replaced by acusto-optodeflectors, adaptive optics deflectors or regular beam splitters (50/50splitters, for example). In the case of using regular beam splitters,portions of the laser beam 302 will be present in both the fast path 319and the slow path 316. Shutters are present in each of the fast and slowpaths so that one is closed at any moment of time, the laser beam willtravel in the path that is not closed.

The previously described systems 300 and 700 of FIGS. 4 and 8 operatedon the principle of separating the fast and slow laser beams in separatepaths. As shown in FIGS. 9 and 10, it is possible to generate fast andslow laser beams on a common path. Regarding the embodiment shown inFIG. 9, a beam delivery optical system 800 includes a laser beam 302that is generated by a laser source 304 and directed via mirrors 306,308 to a variable divergence afocal system 332. As shown in FIG. 9, thelaser beam 302 is transformed by a variable aperture 802 that can bepositioned at various locations along the single path. In operation, thevariable aperture 802 is controlled to have a first aperture size thatwill generate a laser beam with a F/# that has a value that is similarto the laser beam present in the slow paths of the systems 300 and 700of FIGS. 4 and 7. The variable aperture 802 can also be controlled tohave a second aperture size that will generate a laser beam with a F/#that has a value that is similar to the laser beam present in the fastpaths of the systems 300 and 700 of FIGS. 4 and 7. After the particularlaser beam (fast or slow) is formed, it passes through the x-y scanner326, scan lens 328 and aspheric patient interface device 330 in a mannersimilar as described previously with respect to systems 300 and 700 ofFIGS. 4 and 7. The fast and slow beams are scanned in the z-direction bythe scan lens 328 and afocal system 332, respectively, in the mannerdescribed previously with respect to FIGS. 4 and 7.

Note that in the alternate embodiment of FIG. 10, a beam deliveryoptical system 900 is identical to that of system 800 of FIG. 9 whereinvariable aperture 802 is replaced by a variable magnification beamexpander 902, such as the Motorized Zoom Beam Expander Models VIS-NIR56C-30-1-4x-λ and 2-8X-λ, manufactured and sold by Special Optics ofWharton, N.J. Instead of varying an aperture size to generate differentF/# laser beams as in FIG. 9, the beam expander 902 changes themagnification of the laser beam so as to have different F/# values.Thus, system 900 operates in a manner similar to that of system 800.

An embodiment of a beam delivery optical system 1000 that can form cutsin the cornea 202, anterior capsule 203 and crystalline lens 204 withboth low F/# (forming cuts in cornea 202 and anterior capsule 203) andhigh F/# (forming cuts in crystalline lens 204) types of beams isillustrated in FIG. 11. In particular, a laser beam 302 is generated bya laser source 304 and directed via mirrors 306, 308 to an opticalswitch 310. The optical switch 310 includes a λ/2 wave plate 312 and apolarization beam splitter cube (PBSC) 314. Rotating a λ/2 wave plate bya certain angle rotates the polarization of an incident linearlypolarized beam by double the certain angle, so the λ/2 wave plate 312 inthe optical switch 310 acts as a polarization rotator. A PBSC reflectsall light with the polarization parallel to the plane of the PBSC'sreflective surface and transmits all light with the polarization 90degrees rotated with respect to the reflected polarization. With theabove said, as the laser beam 302 is linearly polarized, rotating theλ/2 wave plate 312 to a first position allows the laser beam 302 to passentirely through the PBSC 314 to travel along a fast path 319 and not aslow path 316 of the system 300. Rotating the λ/2 wave plate 312 by 45degrees with respect to the first position allows the laser beam 302 tobe entirely reflected by the PBSC 314 and directed to a mirror 318 sothat the laser beam 302 travels along the slow path 316 and not the fastpath 319. Thus, the optical switch 310 switches the laser beam 302between the fast path 319 and the slow path 316, wherein only one pathat a time is used during cutting. During the time the λ/2 wave plate 312rotates by 45 degrees to switch between the slow path 316 and the fastpath 319, the laser will be shut off. So, it will be a short delayduring which the laser beam will be “off” allowing for the opticalswitch 310 to completely switch between the two paths.

In the fast path 319, the laser beam 302 passes through an adaptiveoptic device 1001 that is programmed to dynamically correct theaberrations introduced in the laser beam by refractions at variousinterfaces between transparent materials or tissue as the laser beam isfocused at different depths and different radial positions throughoutthe three-dimensional working space A or B (see hashed line area A ofcornea 202 of FIG. 3 and hashed line areas B in the vicinity of theanterior capsule 203 of the crystalline lens 204 of FIG. 3). After beingcorrected by the adaptive optic device 1001, the laser beam 302 isexpanded by a beam expander 320 with a magnification equal to the ratiobetween the F/# of the beam directed along the slow path 316 and the F/#of the laser beam directed along the fast path 319. The expansion of thebeam 302 by beam expander 320 is equivalent to expanding the entrancepupil diameter D and so the F/# is reduced. Thus, beam expander 320 actsas an F/# varying element. Note that the particular magnification forbeam expander 320 is chosen in view of the fact that the beam in theslow path 316 is not expanded. The expanded laser beam 322 leaving beamexpander 320 is then directed through a second PBSC 324 and passed on toan x-y-z translation device 1003. The x-y-z translation device 1003relays the laser beam from the fast path 319 or the slow path 316 into arotating optical system 1002 along the axis of rotation 1004 of therotating optical system 1002. The x-y-z translation device 1003 is usedto center a circular cutting pattern 1006 at desired x-y coordinates inthe eye 200. The x-y-z translation device 1003 is also used to move orscan the focused laser beam 334 at the desired depth in the eye 200along the z-axis. The laser beam 322 is relayed by the x-y-z translationdevice 1003 into the rotating optical system 1002, which focuses thelaser beam 334 into the eye (not shown) that is being surgicallyrepaired. The low F/# laser beam 334 focused by the scan lens system 328is then directed by the rotating optical system 1002 to the cornea 202or the anterior capsule 203 wherein incisions or cuts are made theretopursuant to a predetermined pattern. The details regarding the adaptiveoptic device 1001, the x-y-z translation device 1003, and the rotatingoptical system 1002 will be explained later in the present application.

When the optical switch 310 directs light along the slow path 316, thelaser beam 302 is redirected via steering mirrors 318 and 333 into thesecond polarization beam splitter cube (PBSC) 324. As shown in FIG. 11,the fast path 319 and the slow path 316 are recombined by the secondPBSC 324 and both sent into the x-y-z translation device 1003, whichfurther relays the laser beam into the rotating optical system 1002along the axis of rotation 1004. The high F/# laser beam 336 focused bythe rotational optical system 1002 is then directed to the crystallinelens 204 wherein incisions or cuts are made thereto pursuant to apredetermined pattern. Note that since the focused laser beam 336 formedthrough the slow path 316 has a higher F/#, and since a higher F/# beamis not sensitive to aberrations introduced by various refractions of thebeam 336 in the eye, it is not necessary to use an adaptive optic deviceto correct aberrations like in the case where the focused beam 334 isformed through the fast path 319.

Note that the operation of PBSCs 314 and 324 is such that all lightreflected by PBSC 314 into the slow path 316 will be reflected by PBSC324 back onto the optical axis of the x-y-z translation device 1003 dueto the polarization being parallel to the reflecting surface of bothPSCs. Likewise, all light transmitted by PBSC 314 will be transmitted byPBSC 324. The advantage of using PBSCs is that the power loss isminimized through the system since they transmit or reflect all light.

The preferred embodiment of the adaptive optic device 1001 used in thebeam delivery optical system 1000 of FIG. 11 is shown in FIG. 12A. Inparticular, a deformable mirror (DM) 1108 can be used as an adaptiveoptic element. Deformable mirrors are commercially available fromseveral manufacturers, such as Imagine Optic of Orsay, France and BostonMicromachines Corporation of Cambridge, Mass. Referring to FIG. 12A, theinput laser beam 1102 from PBSC 314 enters the adaptive optic device1001 via a PBSC 1104 such that the beam is directed through a quarterwave-plate (QWP) 1106 along a path normal to the surface of the DM 1108.The QWP 1106 has the role of converting the linear polarized light ofthe input beam 1102 into circular polarized light, and after reflectionoff of the DM 1108, the QWP 1106 converts the circular polarized lightback into linear polarized light. However, after the double pass throughthe QWP 1106, the linear polarization of an output beam 1110 turns by 90degrees with respect to the linear polarization of the input beam 1102,so the output beam 1110 exits from the alternate facet of the PBSC 1104.The advantage of this embodiment is that the laser beam is directednormal to the DM 1108, maximizing the dynamic range of the DM 1108.

In an alternate embodiment, adaptive optic device 1001′ shown in FIG.12B can be used in the beam delivery optical system 1000 of FIG. 11,wherein the input beam 1102 is reflected by a first reflective surface1212 into the DM 1108, then further reflected into a second reflectivesurface 1214, which reflects the output beam 1110.

Note that the DM 1108 can be replaced by other types of adaptive opticelements, such as a liquid crystal spatial light modulator, availablefrom Boulder Nonlinear Systems of Lafayette, Colo. Also, note that theposition of the adaptive optic device 1001, 1001′ in the beam deliveryoptical system 1000 of FIG. 11 can be changed without departing from thespirit of the present invention. For example; the adaptive optic device1001, 1001′ can be placed anywhere along the laser beam path between thelaser 304 and the optical switch 310, before or after the beam expander320 along the laser beam in the fast path 319, or between the PBSC 324and the rotating optical system 1002 along the laser beam.

The preferred embodiment of the x-y-z translation device 1003 isrepresented schematically in FIG. 13. The input beam 1302 from eitherthe slow path 316 or fast path 319 enters the x-y-z translation device1003 parallel to the x-axis of movement of a first linear translationstage 1304 and is reflected by 90 degrees by a first mirror 1306 that ismounted onto the first translation stage 1304. After the reflection offof the first mirror 1306, the beam 1302 travels parallel to the y-axisof movement of a second linear translation stage 1308 and is reflectedby 90 degrees by a second mirror 1310 that is mounted onto the secondlinear translation stage 1308. The second linear translation stage 1308is mounted onto the first linear translation stage 1304. As shown inFIG. 13, an aperture 1312 is formed in the center of the second lineartranslation stage 1308 so as to allow the beam 1302 reflected by mirror1310 to pass therethrough. After the reflection off of the second mirror1310, the beam 1302 travels parallel to the z-axis of movement of athird linear translation stage 1314, through an opening 1316 of thethird linear translation stage 1314, and along the axis of rotation ofthe rotating optical system 1002. The x-, y- and z-axes of movement areperpendicular to one another.

Other embodiments for the x-y-z translation device are possible. Forexample; the x-y-z staggered linear translation stages of FIG. 13 couldbe replaced by a motorized hexapod structure and the laser beam could berelayed into the rotating optical system 1002 by an articulatedopto-mechanical arm that would allow translation of the beam in thex-y-z directions. Another method to translate the laser beam is toeliminate the x-y-z translation device 1003 and place the entire lasersystem (including laser source and rotating optical system) on aplatform capable of moving in the x-y-z directions.

The preferred embodiment of the rotating optical system 1002 isrepresented schematically in FIG. 14. The first three mirrors 1402,1404, 1406 in the rotating optical system are fixed with respect to therotation stage 1408 (an alternate embodiment for these three fixedmirrors can be a multi-facet prism with three reflective surfaces). Afourth mirror 1410 is mounted together with a focusing lens 1412 onto aradial displacement linear stage 1414 (7-8 mm total motion range), whichis mounted to the rotation stage 1408. The laser beam generated from thefast path 319 or the slow path 316 is relayed from the x-y-z translationdevice 1003 into the rotating optical system 1002 along the axis ofrotation. The laser beam is reflected by the first three mirrors 1402,1404, 1406 as shown in FIG. 14 and relayed into the fourth mirror 1410,which directs the laser beam through the focusing lens 1412. When theradial displacement linear stage 1414 is at its 0 position, the focus ofthe laser beam remains stationary while the rotation stage is in motion.As the radial displacement linear stage 1414 moves away from the axis ofrotation by an amount R, the focus of the laser beam describes a circle1330 of radius R while the rotation stage 1002 is in motion.

Cuts or incisions formed in the eye that are rotationally symmetricabout the axis of rotation can be performed at arbitrary radialpositions and z depths (within the range of the linear translationstages) using the radial displacement linear stage 1414 in the rotatingoptical system 1002 in conjunction with the z linear stage in the x-y-ztranslation device 1003. Therefore, the ophthalmic laser systemdescribed in the present invention is ideal for performing cuts orincisions in the cornea and anterior capsule of the crystalline lens(such as CCIs, LRIs, and capsulotomy), which are typically rotationallysymmetric patterns about the apex of the cornea or about the apex of theanterior capsule of the crystalline lens. FIG. 15 shows a top view oftypical arcuate incisions/cuts that are made along one or more circularpatterns in the case where the beam is formed through the fast path 319.

However, all the above mentioned cuts or incisions in the eye are donewith a fast laser beam, and therefore the aberrations in the laser beamwould have to be corrected using the adaptive optic device 1001, 1001′in conjunction with the real-time position of the beam focus (waist)into the eye. After the three-dimensional biometrics are measured forthe eye to be treated (all positions, thicknesses, and radii ofcurvature of the cornea, anterior chamber, and crystalline lens), thedesired patterns of all cuts and incisions are programmed into thesystem. Then, the optical aberrations introduced in the laser beam dueto refractions through the transparent tissue are calculatedtheoretically and mapped throughout the three-dimensional space based onthe biometrics and the programmed cuts and incisions patterns.Aberrations in the laser beam will vary with the position of the focusin z (controlled by the z stage 1314 in the x-y-z translation device1003), radial displacement (controlled by the radial displacement linearstage 1414 in the rotating optical system 1002), and azimuth angle(controlled by the position of the rotating stage 608). The adaptiveoptic device 1001, 1001′ is then programmed to correct these aberrationsin real time as a function of the three-dimensional position of thelaser beam focus with respect to the measured biometrics. FIG. 16Aschematically represents the case where an unaberrated wavefront isdirected to optics which results in aberrated wavefronts after passingthrough a cover window, a cornea and other portions of an eye beforearriving at a focal point. FIG. 16B schematically represents an examplewhere, in the case where the beam is formed through the fast path, theaberrations introduced in the laser beam by refractions at varioustransparent interfaces are corrected by the adaptive optic device. Notethat the adaptive optic device 1001, 1001′ will have to dynamicallychange the compensating wavefront in real-time to follow the change inaberrations with the relative position of the laser beam focus into thetreated eye.

In the case of the crystalline lens fragmentation cuts, which are donewith the slow laser beam (large F/#), transversal arc shaped cuts aretypically used along with circular cuts to form pie shaped pieces (seetriangular-like pieces near center of pattern) and rectangular-likepieces (see pieces positioned away from center of pattern) as shownschematically in FIG. 17A. A possible process for forming the circularcuts of FIG. 17A would be to turn off the laser and move the axis ofrotation of the optical system 1002 via the x-y-z translation device1003 so as to coincide with the axis of the eye. Next, the radialposition of the laser beam (either 334, 336) emitted from the opticalsystem 1002 is controlled by translating the radial translation stage1414. Next, the z-position of the focus of the laser beam is controlledby the linear translation stage 1314 of the x-y-z-translation device1003. Once the radial and z positions are set, the laser is turned onand full rotation of the rotating stage 1408 results in a circular cutbeing formed at a particular depth of the eye. Other circular cuts canbe formed by varying the depth of the focused laser beam in the eye andvarying the radius of rotation by moving the linear translation stage1314 and rotating stage 1408.

As shown in FIG. 17A, pie-shaped pieces and rectangular-like pieces canbe formed by the previously described circular cuts and transversalarc-shaped cuts that are transverse to the circular cuts. With the abovesaid, the laser is turned off and a desired radius of curvature of thetransversal arc-shaped cut is obtained by varying the radial translationstage 1414 until the desired radius of curvature is achieved. Next, thepath of the transversal arc-shaped cut is selected by translating theaxis of rotation of the optical system 1002 to a position so that thecut will intersect the center of the eye and two points on the maximumfragmentation diameter (see FIG. 17B). Next, the rotating stage 1408 isrotated so that when the laser is turned on, the laser beam is focusedat one of the two points mentioned previously. The rotating stage 1408continues to rotate while the laser beam follows an arcuate path untilit reaches the second point at which the laser is turned off. Othertransversal arc-shaped cuts can be formed by varying the depth of thefocused laser beam in the eye by moving the linear translation stage1314. Other transversal arc-shaped cuts can be formed by turning thelaser off and translating the axis of rotation of the optical system1002 other positions by moving the linear stages 1304 and 1308.

Note that other embodiments for a dual beam delivery optical system arepossible. An example of such an optical system is the beam deliveryoptical system 1500 shown in FIG. 18. The structure of beam deliveryoptical system 1500 is similar to beam delivery optical system 1000 ofFIG. 11. In particular, a laser beam 302 is generated by a laser source304 and directed via mirrors 306, 308 to an optical switch 310. Incontrast to the λ/2 wave plate 312 and polarization beam splitter cube(PBSC) 314 of FIG. 11, the system 1500 uses a turning mirror 1502 thatcan rotate to a first position so that the laser beam 302 is directed tomirror 318 and the slow path in a manner as described with respect tothe embodiment of FIG. 11. Rotating turning mirror 1502 causes the laserbeam 302 to reflect off of mirror 1504 and directed to the fast path tobe processed by the adaptive optic device 1001, 1001′ and the beamexpander 320 in a manner as described with respect to the embodiment ofFIG. 11.

As shown in FIG. 18, the fast path laser beam is deflected by a mirror1508 to a second turning mirror 1506 which is positioned at a firstposition to reflect the fast path laser beam to the x-y-z translationdevice 1003. Similarly, the slow path laser beam is deflected by amirror 333 to the turning mirror 1506 which is positioned at a secondposition to reflect the slow path laser beam to the x-y-z translationdevice 1003. The slow path and fast path laser beams are processed,relayed and focused by the adaptive optic device 1001, 1001′, x-y-ztranslation device 1003 and rotating optical system 1002 in a mannersimilar to that described with respect to the embodiment of FIG. 11.

Note that in operation, the rotation of mirrors 1502 and 1506 aresynchronized so that the laser beam 302 passes through either only thefast path 319 or the slow path 316. In addition, the laser beam 302 isstopped or the laser 304 is shut off during rotation of the mirrors 1502and 1506.

Other possibilities for the optical switch 310 of FIG. 15 are possible.For example, the mirrors 1502 and 1506 can be replaced by acusto-optodeflectors, adaptive optics deflectors or regular beam splitters (50/50splitters, for example). In the case of using regular beam splitters,portions of the laser beam 302 will be present in both the fast path 319and the slow path 316. Shutters are present in each of the fast and slowpaths so that one is closed at any moment of time, the laser beam willtravel in the path that is not closed.

The previously described systems 1000 and 1500 of FIGS. 11 and 18operated on the principle of separating the fast and slow laser beams inseparate paths. As shown in FIGS. 19 and 20, it is possible to generatefast and slow laser beams on a common path. Regarding the embodimentshown in FIG. 19, a beam delivery optical system 1600 includes a laserbeam 302 that is generated by a laser source 304 and directed viamirrors 306, 308 to an adaptive optic device 1001, 1001′ and a beamexpander 320. As shown in FIG. 19, the laser beam 302 is transformed bya variable aperture 1602 that can be positioned at various locationsalong the single path. In operation, the variable aperture 1602 iscontrolled to have a first aperture size that will generate a laser beamwith a F/# that has a value that is similar to the laser beam present inthe slow paths of the systems 1000 and 1500 of FIGS. 11 and 18. Thevariable aperture 1602 can also be controlled to have a second aperturesize that will generate a laser beam with a F/# that has a value that issimilar to the laser beam present in the fast paths of the systems 1000and 1500 of FIGS. 11 and 18. After the particular laser beam (fast orslow) is formed, it passes through the x-y-z translation device 1003 andthe rotating optical system 1002 in a manner similar as describedpreviously with respect to systems 1000 and 1500 of FIGS. 11 and 18.

Note that in the alternate embodiment of FIG. 20, a beam deliveryoptical system 1700 is nearly identical to that of system 1600 of FIG.19 wherein variable aperture 1602 is replaced by a variablemagnification beam expander 1702, such as the Motorized Zoom BeamExpander Models VIS-NIR 56C-30-1-4x-λ and 2-8X-λ, manufactured and soldby Special Optics of Wharton, N.J. Instead of varying an aperture sizeto generate different F/# laser beams as in FIG. 19, the beam expander1702 changes the magnification of the laser beam so as to have differentF/# values. Thus, system 1700 operates in a manner similar to that ofsystem 1600. Note that beam expander 1702 can also be positioned withinlaser 304, between laser 304 and mirror 306, between mirrors 306 and308, and between mirror 308 and adaptive optic 1001, 1001′.

It will be appreciated by those skilled in the art that changes could bemade to the embodiments described above without departing from the broadinventive concept thereof. It is understood, therefore, that thisinvention is not limited to the particular embodiments disclosed, but itis intended to cover modifications within the spirit and scope of thepresent invention as defined by the appended claims. For example, otheroptical elements can be used for switching between the fast and slowpaths of FIGS. 4, 8-11 and 18-20. In addition, additional opticalconfigurations and/or elements can be used for items 332, 328 and/or1002 of FIGS. 4, 8-11, 14 and 18-20 without departing from the spirit ofthe invention.

We claim:
 1. An ophthalmic laser system comprising: a laser source that generates a laser beam; an optical switch that receives said laser beam and selectively sends said laser beam to either a fast path or a slow path, wherein in said fast path said laser beam has a first F/# and in said slow path said laser beam has a second F/# that is higher in value than said first F/#; an adaptive optic device that is in said fast path and receives said laser beam from said optical switch; an x-y-z translation device that receives either a first laser beam from said slow path or a second laser beam from said fast path; and a rotating optical system that receives a laser beam from said x-y-z translation device and performs a partial or full circular scan of said received laser beam about an axis of rotation of said rotating optical system, wherein said rotating optical system is able to translate so as to vary a radius of said partial or full circular scan and said partial or full circular scan is positioned in an eye of a patient; and wherein said adaptive optic corrects said laser beam received from said fast path so that aberrations at said partial or full circular scan are significantly reduced.
 2. The ophthalmic laser system of claim 1, wherein said optical switch comprises a X/2 wave plate and a polarization beam splitter cube in series with one another.
 3. The ophthalmic laser system of claim 1, wherein said optical switch comprises a turning mirror that can rotate to a first position so that said laser beam is directed to said slow path and can rotate to a second position so that said laser beam is directed to said fast path.
 4. The ophthalmic laser system of claim 1, wherein said optical switch comprises an acusto-opto deflector.
 5. The ophthalmic laser system of claim 1, wherein said optical switch comprises an adaptive optics deflector.
 6. The ophthalmic laser system of claim 1, wherein said optical switch comprises a regular beam splitter.
 7. The ophthalmic laser system of claim 1, further comprising a beam expander in the fast path that receives said laser beam from said optical switch.
 8. The ophthalmic laser system of claim 7, wherein a magnification of a laser beam generated by said beam expander is equal to the ratio: first F/#/second F/#.
 9. The ophthalmic laser system of claim 1, wherein said adaptive optic comprises a beam splitting device that receives from said optical switch said laser beam in said fast path and directs said laser beam in said fast path to a deformable mirror and said deformable mirror redirects said laser beam in said fast path to said beam splitting device which in turn directs said laser beam toward said x-y-z translation device.
 10. The ophthalmic laser system of claim 9, wherein said beam splitting device comprises a polarization beam splitter cube.
 11. The ophthalmic laser system of claim 10, further comprising a quarter wave plate that receives said laser beam in said fast path from said beam splitting device and directs said laser beam in said fast path to said deformable mirror.
 12. The ophthalmic laser system of claim 9, wherein said rotating optical system comprises: a rotation stage that rotates about said axis of rotation and receives either said first laser beam or said second laser beam from said x-y-z translation device; and a radial translation stage is positioned within said rotation stage so as to rotate with said rotation stage, wherein said radial translation stage translates relative to said rotation stage and comprises a lens that receives and focuses either said first laser beam or said second laser beam from said rotation stage.
 13. The ophthalmic laser system of claim 1, wherein said rotating optical system comprises: a rotation stage that rotates about said axis of rotation and receives either said first laser beam or said second laser beam from said x-y-z translation device; and a radial translation stage is positioned within said rotation stage so as to rotate with said rotation stage, wherein said radial translation stage translates relative to said rotation stage and comprises a lens that receives and focuses either said first laser beam or said second laser beam from said rotation stage.
 14. An ophthalmic laser system comprising: a laser source that generates a laser beam; an optical switch that receives said laser beam and selectively transforms said laser beam to either a fast path laser beam or a slow path laser beam, wherein said fast path laser beam has a first F/# and said slow path laser beam has a second F/# that is higher in value than said first F/#; an adaptive optic device that receives either said fast path laser beam or said slow path laser beam from said optical switch; an x-y-z translation device that receives either said fast path laser beam or said slow path laser beam from said adaptive optic; and a rotating optical system that receives a laser beam from said x-y-z translation device and performs a partial or full circular scan of said received laser beam about an axis of rotation of said rotating optical system, wherein said rotating optical system is able to translate so as to vary a radius of said partial or full circular scan and said partial or full circular scan is positioned in an eye of a patient; and wherein said adaptive optic corrects said fast laser beam so that aberrations along said partial or full circular scan are significantly reduced.
 15. The ophthalmic laser system of claim 14, wherein said optical switch comprises a beam expander.
 16. The ophthalmic laser system of claim 14, wherein said optical switch comprises a variable magnification beam expander.
 17. A method of surgically repairing an eye comprising: generating a laser beam; selectively manipulating said laser beam so that said laser beam is present in either a fast path or a slow path, wherein in said fast path said laser beam has a first F/# and in said slow path said laser beam has a second F/# that is higher in value than said first F/#; having an adaptive optic device that is in said fast path to receive said selectively manipulated laser beam in said fast path; having an x-y-z translation device that receives either said fast path laser beam or said slow path laser beam from said adaptive optic; receiving a laser beam from said x-y-z translation device and performing a partial or full circular scan of said received laser beam and varying a radius of said circular scan, wherein said partial or full circular scan is positioned in an eye of a patient, and wherein said adaptive optic corrects said laser beam received from said fast path so that aberrations along said partial or full circular scan are significantly reduced. 